Dewaxing process using zeolite SSZ-25

ABSTRACT

A crystalline zeolite SSZ-25 is prepared using an adamantane quaternary ammonium ion as a template.

This is a divisional of Ser. No. 07/897,222 filed Jun. 11, 1992, nowU.S. Pat. No. 5,421,992, which is a continuation of Ser. No. 788,656filed Nov. 6, 1991, now U.S. Pat. No. 5,202,014, which is a continuationof Ser. No. 333,666 filed Apr. 5, 1989 (now abandoned), which is adivisional of Ser. No. 14,958 filed Feb. 17, 1987, now U.S. Pat. No.4,826,667.

BACKGROUND OF THE INVENTION

Natural and synthetic zeolitic crystalline aluminosilicates are usefulas catalysts and adsorbents. These aluminosilicates have distinctcrystal structures which are demonstrated by X-ray diffraction. Thecrystal structure defines cavities and pores which are characteristic ofthe different species. The adsorptive and catalytic properties of eachcrystalline aluminosilicate are determined in part by the dimensions ofits pores and cavities. Thus, the utility of a particular zeolite in aparticular application depends at least partly on its crystal structure.

Because of their unique molecular sieving characteristics, as well astheir catalytic properties, crystalline aluminosilicates are especiallyuseful in such applications as gas drying and separation and hydrocarbonconversion. Although many different crystalline aluminosilicates andsilicates have been disclosed, there is a continuing need for newzeolites and silicates with desirable properties for gas separation anddrying, hydrocarbon and chemical conversions, and other applications.

Crystalline aluminosilicates are usually prepared from aqueous reactionmixtures containing alkali or alkaline earth metal oxides, silica, andalumina. "Nitrogenous zeolites" have been prepared from reactionmixtures containing an organic templating agent, usually anitrogen-containing organic cation. By varying the synthesis conditionsand the composition of the reaction mixture, different zeolites can beformed using the same templating agent. Use of N,N,N-trimethylcyclopentyl-ammonium iodide in the preparation of Zeolite SSZ-15molecular sieve is disclosed in my co-pending application Ser. No.437,709, filed on Oct. 29, 1982; use of 1-azoniaspiro [4.4] nonylbromide and N,N,N-trimethyl neopentylammonium iodide in the preparationof a molecular sieve termed "Losod" is disclosed in Helv. Chim. Acta(1974); Vol. 57, page 1533 (W. Sieber and W. M. Meier); use ofquinuclidinium compounds to prepare a zeolite termed "NU-3" is disclosedin European Patent Publication No. 40016; use of 1,4-di(1-azoniabicyclo[2.2.2.]octane) lower alkyl compounds in the preparation of ZeoliteSSZ-16 molecular sieve is disclosed in U.S. Pat. No. 4,508,837; use ofN,N,N-trialkyl-1-adamantamine in the preparation of Zeolite SSZ-13molecular sieve is disclosed in U.S. Pat. No. 4,544,538.

SUMMARY OF THE INVENTION

I have prepared a family of crystalline aluminosilicate molecular sieveswith unique properties, referred to herein as "Zeolite SSZ-25", orsimply "SSZ-25", and have found a highly effective method for preparingSSZ-25.

SSZ-25 has a mole ratio of an oxide selected from silicon oxide,germanium oxide, and mixtures thereof to an oxide selected from aluminumoxide, gallium oxide, iron oxide, boron oxide and mixtures thereof inthe range of 20 to 200, and having the X-ray diffraction lines of Table1 below. The zeolite further has a composition, as synthesized and inthe anhydrous state, in terms of mole ratios of oxides as follows: (0.1to 2.0)(Q₂ O:(0.1 to 2.0)M₂ O:W₂ O₃ :(20 to 200)YO₂ wherein M is analkali metal cation, W is selected from aluminum, gallium, iron, boronand mixtures thereof, Y is selected from silicon, germanium and mixturesthereof, and Q is an adamantane quaternary ammonium ion. SSZ-25 zeolitescan have a YO₂ :W₂ O₃ mole ratio in the range of 20 to 200. As prepared,the silica:alumina mole ratio is typically in the range of 30:1 to about100:1. Higher mole ratios can be obtained by treating the zeolite withchelating agents or acids to extract aluminum from the zeolite lattice.The silica:alumina mole ratio can also be increased by using silicon andcarbon halides and other similar compounds. Preferably, SSZ-25 is analuminosilicate wherein W is aluminum and Y is silicon.

My invention also involves a method for preparing SSZ-25 zeolites,comprising preparing an aqueous mixture containing sources of anadamantane quaternary ammonium ion, an oxide selected from aluminumoxide, gallium oxide, iron oxide, boron oxide and mixtures thereof, andan oxide selected from silicon oxide, germanium oxide, and mixturesthereof, and having a composition, in terms of mole ratios of oxides,falling within the following ranges: YO₂ /W₂ O₃, 20:1 to 200:1; and Q₂O/YO₂, 0.15:1 to 0.50:1; wherein Y is selected from silicon, germanium,and mixtures thereof, W is selected from aluminum, gallium, iron, boronand mixtures thereof, and Q is an adamantane quaternary ammonium ion;maintaining the mixture at a temperature of at least 100° C. until thecrystals of said zeolite are formed; and recovering said crystals.

DETAILED DESCRIPTION OF THE INVENTION

SSZ-25 zeolites, as synthesized, have a crystalline structure whoseX-ray powder diffraction pattern shows the following characteristiclines:

                  TABLE 1                                                         ______________________________________                                        2 θ       d/n    I/I.sub.o                                              ______________________________________                                        3.05            29.0   20                                                     6.42            13.77  100                                                    7.18            12.31  100                                                    7.88            11.22  47                                                     9.62            9.19   53                                                     15.75           5.63   27                                                     19.37           4.58   47                                                     22.57           3.94   50                                                     23.05           3.86   30                                                     26.03           3.42   73                                                     26.85           3.32   33                                                     ______________________________________                                    

Typical SSZ-25 aluminosilicate zeolites have the X-ray diffractionpattern of Tables 3-5.

The X-ray powder diffraction patterns were determined by standardtechniques. The radiation was the K-alpha/doublet of copper and ascintillation counter spectrometer with a strip-chart pen recorder wasused. The peak heights I and the positions, as a function of 2 θ where θis the Bragg angle, were read from the spectrometer chart. From thesemeasured values, the relative intensities, 100I/I₀, where I₀ is theintensity of the strongest line or peak, and d, the interplanar spacingin Angstroms corresponding to the recorded lines, can be calculated. TheX-ray diffraction pattern of Table 1 is characteristic of SSZ-25zeolites. The zeolite produced by exchanging the metal or other cationspresent in the zeolite with various other cations yields substantiallythe same diffraction pattern although there can be minor shifts ininterplanar spacing and minor variations in relative intensity. Minorvariations in the diffraction pattern can also result from variations inthe organic compound used in the preparation and from variations in thesilica-to-alumina mole ratio from sample to sample. Calcination can alsocause minor shifts in the X-ray diffraction pattern. Notwithstandingthese minor perturbations, the basic crystal lattice structure remainsunchanged.

After calcination, the SSZ-25 zeolites have a crystalline structurewhose X-ray powder diffraction pattern shows the followingcharacteristic lines as indicated in Table 2 below:

                  TABLE 2                                                         ______________________________________                                        2 θ       d/n     I/I.sub.o                                             ______________________________________                                        3.4             25.5    17                                                    7.19            12.30   100                                                   8.04            11.00   55                                                    10.06           8.78    63                                                    14.35           6.17    40                                                    16.06           5.51    17                                                    22.77           3.90    38                                                    23.80           3.74    20                                                    26.08           3.417   65                                                    ______________________________________                                    

The equilibrium sorption for water and n-hexane of SSZ-25 are listed inTable 3. These equilibrium sorption capacities were obtained on SSZ-25samples prepared as described in Example 6.

                  TABLE 3                                                         ______________________________________                                        Equilibrium Sorption Capacities of SSZ-25                                     ______________________________________                                        Amount of N-Hexane Sorbed (g/100 g activated sample)                          Zeolite Sample P/Po = 0.20                                                    ______________________________________                                        A              0.111                                                          B              0.121                                                          C              0.107                                                          D              0.106                                                          ______________________________________                                        Amount of H.sub.2 O Sorbed (g/100 g activated sample)                         Zeolite Sample P/Po = 0.57                                                                              P/Po = 0.20                                         ______________________________________                                        E              0.126      0.063                                               ______________________________________                                    

Based on the measurements made with n-hexane, the equilibrium sorptioncapacity of SSZ-25 is greater than 10 wt. %.

These equilibrium sorption capacities were obtained using the methoddescribed in "Method for Rapid Determination of Adsorption Properties ofMolecular Sieves", G. R. Landolt, Analytical Chemistry, Vol. 43, No. 4,613-615. Based on this method, the zeolites were dried by heating themovernight at 650° F. in air and weighed. They were then loaded intoampoules, placed in the adsorption chamber, and evacuated to less than 1micron. The adsorbate had been outgassed on the vacuum line and so onlythe vapor was in contact with the zeolite (no air). The samples wereconnected to the adsorbate, either water or n-hexane. The vapor pressureof the adsorbate was measured with a pressure transducer. Equilibriumsorption measurements were made at several P/Po values and the samplesare at 22° C. (72° F.).

Equilibration was obtained in 3-6 hours. After equilibration, thesamples were removed and weighed to determine the amount adsorbed. Thevapor pressure of the adsorbate was controlled by immersing a glassvessel containing the latter in a temperature-controlled cryostat. P/Pomay be varied over a wide range by adjusting the temperature of theadsorbate.

This approach differs from the approach used by Landolt; in that, wecheck if air has leaked into the adsorption chamber by monitoring thepressure during the adsorption. The pressure should agree with publishedvapor pressure/temperature data for that particular adsorbate at thetemperature of the cryostat. If the pressure is higher, we know we havea leak which we have to correct. If air is present in the adsorptionchamber, the rate of adsorption decreases and equilibrium may not beattained in the allotted time.

SSZ-25 zeolites can be suitably prepared from an aqueous solutioncontaining sources of an alkali metal oxide, an adamantane quaternaryammonium ion, an oxide of aluminum, gallium, iron, boron or mixturesthereof, and an oxide of silicon or germanium, or mixture of the two.The reaction mixture should have a composition in terms of mole ratiosfalling within the following ranges:

    ______________________________________                                                      Broad  Preferred                                                ______________________________________                                        YO.sub.2 /W.sub.2 O.sub.3                                                                      20-200   30-100                                              OH.sup.- /YO.sub.2                                                                            0.10-1.0 0.20-0.40                                            Q/YO.sub.2      0.15-0.50                                                                              0.15-0.30                                            M.sup.+ /YO.sub.2                                                                             0.05-0.30                                                                              0.15-0.30                                            H.sub.2 O/YO.sub.2                                                                             20-300  35-60                                                Q/Q+M.sup.+     0.30-0.70                                                                              0.40-0.67                                            ______________________________________                                    

wherein Q is an adamantane quaternary ammonium ion, Y is silicon,germanium or both, and W is aluminum, gallium, iron, boron or mixturethereof. M is an alkali metal, preferably sodium or potassium. Theorganic adamantane compound which acts as a source of the adamantanequaternary ammonium ion employed can provide hydroxide ion.

When using the adamantane quaternary ammonium hydroxide compound as atemplate, it has also been found that purer forms of SSZ-25 are preparedwhen there is an excess of the adamantane quaternary ammonium hydroxidecompound present relative to the amount of alkali metal hydroxide andthat when the OH⁻ /SiO₂ molar ratio is greater than 0.40, then M⁺ /SiO₂molar ratio should be less than 0.20.

The adamantane quaternary ammonium ion component Q, of thecrystallization mixture, is derived from an adamantane quaternaryammonium compound. Preferably, the adamantane quaternary ammonium ion isderived from a compound of the formula: ##STR1## wherein each of Y₁, Y₂and Y₃ independently is lower alkyl and most preferably methyl; A.sup.θis an anion which is not detrimental to the formation of the zeolite;and each of R₁, R₂, and R₃ independently is hydrogen, or lower alkyl andmost preferably hydrogen; and ##STR2## wherein each of R₄, R₅ and R₆independently is hydrogen or lower alkyl; and most preferably hydrogen;each of Y₁, Y₂ and Y₃ independently is lower alkyl and most preferablymethyl; and A.sup.θ is an anion which is not detrimental to theformation of the zeolite.

The adamantane quaternary ammonium compounds are prepared by methodsknown in the art.

By lower alkyl is meant alkyl of from about 1 to 5 carbon atoms.

A.sup.θ is an anion which is not detrimental to the formation of thezeolite. Representative of the anions include halide, e.g., fluoride,chloride, bromide and iodide, hydroxide, acetate, sulfate, carboxylate,etc. Hydroxide is the most preferred anion. It may be beneficial toion-exchange, for example, the halide for hydroxide ion, therebyreducing or eliminating the alkali metal hydroxide quantity required.

The reaction mixture is prepared using standard zeolitic preparationtechniques. Typical sources of aluminum oxide for the reaction mixtureinclude aluminates, alumina, and aluminum compounds such as AlCl₃ andAl₂ (SO₄)₃. Typical sources of silicon oxide include silicates, silicahydrogel, silicic acid, colloidal silica, tetraalkyl orthosilicates, andsilica hydroxides. Gallium, iron, boron and germanium can be added informs corresponding to their aluminum and silicon counterparts. Salts,particularly alkali metal halides such as sodium chloride, can be addedto or formed in the reaction mixture. They are disclosed in theliterature as aiding the crystallization of zeolites while preventingsilica occlusion in the lattice.

The reaction mixture is maintained at an elevated temperature until thecrystals of the zeolite are formed. The temperatures during thehydrothermal crystallization step are typically maintained from about140° C. to about 200° C., preferably from about 160° C. to about 180°C., and most preferably from about 170° C. to about 180° C. Thecrystallization period is typically greater than 1 day and preferablyfrom about 5 days to about 10 days.

The hydrothermal crystallization is conducted under pressure and usuallyin an autoclave so that the reaction mixture is subject to autogenouspressure. The reaction mixture can be stirred during crystallization.

Once the zeolite crystals have formed, the solid product is separatedfrom the reaction mixture by standard mechanical separation techniquessuch as filtration. The crystals are water-washed and then dried, e.g.,at 90° C. to 150° C. for from 8 to 24 hours, to obtain the assynthesized, SSZ-25 zeolite crystals. The drying step can be performedat atmospheric or subatmospheric pressures.

During the hydrothermal crystallization step, the SSZ-25 crystals can beallowed to nucleate spontaneously from the reaction mixture. Thereaction mixture can also be seeded with SSZ-25 crystals both to direct,and accelerate the crystallization, as well as to minimize the formationof undesired aluminosilicate contaminants. If the reaction mixture isseeded with SSZ-25 crystals, the concentration of the organic compoundcan be greatly reduced or eliminated, but it is preferred to have someorganic compound present, e.g., an alcohol.

The synthetic SSZ-25 zeolites can be used as synthesized or can bethermally treated (calcined). Usually, it is desirable to remove thealkali metal cation by ion exchange and replace it with hydrogen,ammonium, or any desired metal ion. The zeolite can be leached withchelating agents, e.g., EDTA or dilute acid solutions, to increase thesilica:alumina mole ration. The zeolite can also be steamed; steaminghelps stabilize the crystalline lattice to attack from acids. Thezeolite can be used in intimate combination with hydrogenatingcomponents, such as tungsten, vanadium, molybdenum, rhenium, nickel,cobalt, chromium, manganese, or a noble metal, such as palladium orplatinum, for those applications in which ahydrogenation-dehydrogenation function is desired. Typical replacingcations can include metal cations, e.g., rare earth, Group IIA and GroupVIII metals, as well as their mixtures. Of the replacing metalliccations, cations of metals such as rare earth, Mn, Ca, Mg, Zn, Cd, Pt,Pd, Ni, Co, Ti, Al, Sn, Fe and Co are particularly preferred.

The hydrogen, ammonium, and metal components can be exchanged into thezeolite. The zeolite can also be impregnated with the metals, or themetals can be physically intimately admixed with the zeolite usingstandard methods known to the art. And, the metals can be occluded inthe crystal lattice by having desired metals present as ions in thereaction mixture from which the SSZ-25 zeolite is prepared.

Typical ion exchange techniques involve contacting the synthetic zeolitewith a solution containing a salt of the desired replacing cation orcations. Although a wide variety of salts can be employed, chlorides andother halides, nitrates, and sulfates are particularly preferred.Representative ion exchange techniques are disclosed in a wide varietyof patents including U.S. Pat. Nos. 3,140,249; 3,140,251; and 3,140,253.Ion exchange can take place either before or after the zeolite iscalcined.

Following contact with the salt solution of the desired replacingcation, the zeolite is typically washed with water and dried attemperatures ranging from 65° C. to about 315° C. After washing, thezeolite can be calcined in air or inert gas at temperatures ranging fromabout 200° C. to 820° C. for periods of time ranging from 1 to 48 hours,or more, to produce a catalytically active product especially useful inhydrocarbon conversion processes.

Regardless of the cations present in the synthesized form of thezeolite, the spatial arrangement of the atoms which form the basiccrystal lattice of the zeolite remains essentially unchanged. Theexchange of cations has little, if any, effect on the zeolite latticestructures.

The SSZ-25 aluminosilicate can be formed into a wide variety of physicalshapes. Generally speaking, the zeolite can be in the form of a powder,a granule, or a molded product, such as extrudate having particle sizesufficient to pass through a 2-mesh (Tyler) screen and be retained on a400-mesh (Tyler) screen. In cases where the catalyst is molded, such asby extrusion with an organic binder, the aluminosilicate can be extrudedbefore drying, or, dried or partially dried and then extruded. Thezeolite can be composited with other materials resistant to thetemperatures and other conditions employed in organic conversionprocesses. Such matrix materials include active and inactive materialsand synthetic or naturally occurring zeolites as well as inorganicmaterials such as clays, silica and metal oxides. The latter may occurnaturally or may be in the form of gelatinous precipitates, sols, orgels, including mixtures of silica and metal oxides. Use of an activematerial in conjunction with the synthetic zeolite, i.e., combined withit, tends to improve the conversion and selectivity of the catalyst incertain organic conversion processes. Inactive materials can suitablyserve as diluents to control the amount of conversion in a given processso that products can be obtained economically without using other meansfor controlling the rate of reaction. Frequently, zeolite materials havebeen incorporated into naturally occurring clays, e.g., bentonite andkaolin. These materials, i.e., clays, oxides, etc., function, in part,as binders for the catalyst. It is desirable to provide a catalysthaving good crush strength, because in petroleum refining the catalystis often subjected to rough handling. This tends to break the catalystdown into powders which cause problems in processing.

Naturally occurring clays which can be composited with the syntheticzeolites of this invention include the montmorillonite and kaolinfamilies, which families include the sub-bentonites and the kaolinscommonly known as Dixie, McNamee, Georgia and Florida clays or others inwhich the main mineral constituent is halloysite, kaolinite, dickite,nacrite, or anauxite. Fibrous clays such as sepiolite and attapulgitecan also be used as supports. Such clays can be used in the raw state asoriginally mined or can be initially subjected to calcination, acidtreatment or chemical modification.

In addition to the foregoing materials, the SSZ-25 zeolites can becomposited with porous matrix materials and mixtures of matrix materialssuch as silica, alumina, titania, magnesia, silica:alumina,silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia,silica-titania, titania-zirconia as well as ternary compositions such assilica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesiaand silica-magnesia-zirconia. The matrix can be in the form of a cogel.

The SSZ-25 zeolites can also be composited with other zeolites such assynthetic and natural faujasites (e.g., X and Y), erionites, andmordenites. They can also be composited with purely synthetic zeolitessuch as those of the ZSM series. The combination of zeolites can also becomposited in a porous inorganic matrix.

SSZ-25 zeolites are useful in hydrocarbon conversion reactions.Hydrocarbon conversion reactions are chemical and catalytic processes inwhich carbon containing compounds are changed to different carboncontaining compounds. Examples of hydrocarbon conversion reactionsinclude catalytic cracking, hydrocracking, and olefin and aromaticsformation reactions. The catalysts are useful in other petroleumrefining and hydrocarbon conversion reactions such as isomerizingn-paraffins and naphthenes, polymerizing and oligomerizing olefinic oracetylenic compounds such as isobutylene and butene-1, reforming,alkylating, isomerizing polyalkyl substituted aromatics (e.g., orthoxylene), and disproportionating aromatics (e.g., toluene) to providemixtures of benzene, xylenes and higher methylbenzenes. The SSZ-25catalysts have high selectivity, and under hydrocarbon conversionconditions can provide a high percentage of desired products relative tototal products.

SSZ-25 zeolites can be used in processing hydrocarbonaceous feedstocks.Hydrocarbonaceous feedstocks contain carbon compounds and can be frommany different sources, such as virgin petroleum fractions, recyclepetroleum fractions, shale oil, liquefied coal, tar sand oil, and, ingeneral, can be any carbon containing fluid susceptible to zeoliticcatalytic reactions. Depending on the type of processing thehydrocarbonaceous feed is to undergo, the feed can contain metal or befree of metals, it can also have high or low nitrogen or sulfurimpurities. It can be appreciated, however, that in general processingwill be more efficient (and the catalyst more active) the lower themetal, nitrogen, and sulfur content of the feedstock.

Using SSZ-25 catalyst which contains a hydrogenation promoter, heavypetroleum residual feedstocks, cyclic stocks and other hydrocrackatecharge stocks can be hydrocracked at hydrocracking conditions includinga temperature in the range of from 175° C. to 485° C., molar ratios ofhydrogen to hydrocarbon charge from 1 to 100, a pressure in the range offrom 0.5 to 350 bar, and a liquid hourly space velocity (LHSV) in therange of form 0.1 to 30.

The hydrocracking catalysts contain an effective amount of at least onehydrogenation catalyst (component) of the type commonly employed inhydrocracking catalysts. The hydrogenation component is generallyselected from the group of hydrogenation catalysts consisting of one ormore metals of Group VIB and Group VIII, including the salts, complexesand solutions containing such. The hydrogenation catalyst is preferablyselected from the group of metals, salts and complexes thereof of thegroup consisting of at least one of platinum, palladium, rhodium,iridium and mixtures thereof or the group consisting of at least one ofnickel, molybdenum, cobalt, tungsten, titanium, chromium and mixturesthereof. Reference to the catalytically active metal or metals isintended to encompass such metal or metals in the elemental state or insome form such as an oxide, sulfide, halide, carboxylate and the like.

The hydrogenation catalyst is present in an effective amount to providethe hydrogenation function of the hydrocracking catalyst, and preferablyin the range of from 0.05 to 25% by weight.

The catalyst may be employed in conjunction with traditionalhydrocracking catalysts, e.g., any aluminosilicate heretofore employedas a component in hydrocracking catalysts. Representative of thezeolitic aluminosilicates disclosed heretofore as employable ascomponent parts of hydrocracking catalysts are Zeolite Y (includingsteam stabilized, e.g., ultra-stable Y), Zeolite X, Zeolite beta (U.S.Pat. No. 3,308,069), Zeolite ZK-20 (U.S. Pat. No. 3,445,727), ZeoliteZSM-3 (U.S. Pat. No. 3,415,736), faujasite, LZ-10 (U.K. Patent2,014,970, Jun. 9, 1982), ZSM-5-type zeolites, e.g., ZSM-5, ZSM-11,ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48, crystalline silicates such assilicalite (U.S. Pat. No. 4,061,724), erionite, mordenite, offretite,chabazite, FU-1-type zeolite, NU-type zeolites, LZ-210-type zeolite andmixtures thereof. Traditional cracking catalysts containing amounts ofNa₂ O less than about one percent by weight are generally preferred. Therelative amounts of the SSZ-25 component and traditional hydrocrackingcomponent, if any, will depend at least in part, on the selectedhydrocarbon feedstock and on the desired product distribution to beobtained therefrom, but in all instances an effective amount of SSZ-25is employed. When a traditional hydrocracking catalyst (THC) componentis employed, the relative weight ratio of the THC to the SSZ-25 isgenerally between about 1:10 and about 500:1, desirably between about1:10 and about 200:1, preferably between about 1:2 and about 50:1, andmost preferably is between about 1:1 and about 20:1.

The hydrocracking catalysts are typically employed with an inorganicoxide matrix component which may be any of the inorganic oxide matrixcomponents which have been employed heretofore in the formulation ofhydrocracking catalysts including: amorphous catalytic inorganic oxides,e.g., catalytically active silica-aluminas, clays, silicas, aluminas,silica-aluminas, silica-zirconias, silica-magnesias, alumina-borias,alumina-titanias and the like and mixtures thereof. The traditionalhydrocracking catalyst and SSZ-25 may be mixed separately with thematrix component and then mixed or the THC component and SSZ-25 may bemixed and then formed with the matrix component.

SSZ-25 can be used to dewax hydrocarbonaceous feeds by selectivelyremoving straight chain paraffins. The catalytic dewaxing conditions aredependent in large measure on the feed used and upon the desired pourpoint. Generally, the temperature will be between about 200° C. andabout 475° C., preferably between about 250° C. and about 450° C. Thepressure is typically between about 15 psig and about 3000 psig,preferably between about 200 psig and 3000 psig. The liquid hourly spacevelocity (LHSV) preferably will be from 0.1 to 20, preferably betweenabout 0.2 and about 10.

Hydrogen is preferably present in the reaction zone during the catalyticdewaxing process. The hydrogen to feed ratio is typically between about500 and about 30,000 SCF/bbl (standard cubic feet per barrel),preferably about 1000 to about 20,000 SCF/bbl. Generally, hydrogen willbe separated from the product and recycled to the reaction zone. Typicalfeedstocks include light gas oil, heavy gas oils and reduced crudesboiling about 350° F.

The SSZ-25 hydrodewaxing catalyst may optionally contain a hydrogenationcomponent of the type commonly employed in dewaxing catalysts. Thehydrogenation component may be selected from the group of hydrogenationcatalysts consisting of one or more metals of Group VIB and Group VIII,including the salts, complexes and solutions containing such metals. Thepreferred hydrogenation catalyst is at least one of the group of metals,salts and complexes selected from the group consisting of at least oneof platinum, palladium, rhodium, iridium and mixtures thereof or atleast one from the group consisting of nickel, molybdenum, cobalt,tungsten, titanium, chromium and mixtures thereof. Reference to thecatalytically active metal or metals is intended to encompass such metalor metals in the elemental state or in some form such as an oxide,sulfide, halide, carboxylate and the like.

The hydrogenation component is present in an effective amount to providean effective hydrodewaxing catalyst preferably in the range of fromabout 0.05 to 5% by weight.

SSZ-25 can be used to convert light straight run naphthas and similarmixtures to highly aromatic mixtures. Thus, normal and slightly branchedchained hydrocarbons, preferably having a boiling range above about 40°C. and less than about 200° C., can be converted to products having asubstantial aromatics content by contacting the hydrocarbon feed withthe zeolite at a temperature in the range of from about 400° C. to 600°C., preferably 480° C-550° C. at pressures ranging from atmospheric to10 bar, and liquid hourly space velocities (LHSV) ranging from 0.1 to15.

The conversion catalyst preferably contains a Group VIII metal compoundto have sufficient activity for commercial use. By Group VIII metalcompound as used herein is meant the metal itself or a compound thereof.The Group VIII noble metals and their compounds, platinum, palladium,and iridium, or combinations thereof can be used. The most preferredmetal is platinum. The amount of Group VIII metal present in theconversion catalyst should be within the normal range of use inreforming catalysts, from about 0.05 to 2.0 weight percent, preferably0.2 to 0.8 weight percent.

The zeolite/Group VIII metal conversion catalyst can be used without abinder or matrix. The preferred inorganic matrix, where one is used, isa silica-based binder such as Cab-O-Sil or Ludox. Other matrices such asmagnesia and titania can be used. The preferred inorganic matrix isnonacidic.

It is critical to the selective production of aromatics in usefulquantities that the conversion catalyst be substantially free ofacidity, for example by poisoning the zeolite with a basic metal, e.g.,alkali metal, compound. The zeolite is usually prepared from mixturescontaining alkali metal hydroxides and thus have alkali metal contentsof about 1-2 weight percent. These high levels of alkali metal, usuallysodium or potassium, are unacceptable for most catalytic applicationsbecause they greatly deactivate the catalyst for cracking reactions.Usually, the alkali metal is removed to low levels by ion-exchange withhydrogen or ammonium ions. By alkali metal compound as used herein ismeant elemental or ionic alkali metals or their basic compounds.Surprisingly, unless the zeolite itself is substantially free ofacidity, the basic compound is required in the present process to directthe synthetic reactions to aromatics production.

The amount of alkali metal necessary to render the zeolite substantiallyfree of acidity can be calculated using standard techniques based on thealuminum content of the zeolite. Under normal circumstances, the zeoliteas prepared and without ion-exchange will contain sufficient alkalimetal to neutralize the acidity of the catalyst. If a zeolite free ofalkali metal is the starting material, alkali metal ions can be ionexchanged into the zeolite to substantially eliminate the acidity of thezeolite. An alkali metal content of about 100%, or greater, of the acidsites calculated on a molar basis is sufficient.

Where the basic metal content is less than 100% of the acid sites on amolar basis, the test described in U.S. Pat. No. 4,347,394 which patentis incorporated totally herein by reference, can be used to determine ifthe zeolite is substantially free of acidity.

The preferred alkali metals are sodium and potassium. The zeolite itselfcan be substantially free of acidity only at very high silica:aluminamole ratios; by "zeolite consisting essentially of silica" is meant azeolite which is substantially free of acidity without base poisoning.

Hydrocarbon cracking stocks can be catalytically cracked in the absenceof hydrogen using SSZ-25 at liquid hourly space velocities from 0.5 to50, temperatures from about 260° F. to 1625° F. and pressures fromsubatmospheric to several hundred atmospheres, typically from aboutatmospheric to about 5 atmospheres.

For this purpose, the SSZ-25 catalyst can be composited with mixtures ofinorganic oxide supports as well as traditional cracking catalyst.

The catalyst may be employed in conjunction with traditional crackingcatalysts, e.g., any aluminosilicate heretofore employed as a componentin cracking catalysts.

Representative of the zeolitic aluminosilicates disclosed heretofore asemployable as component parts of cracking catalysts are Zeolite Y(including steam stabilized chemically modified, e.g., ultra-stable Y),Zeolite X, Zeolite beta (U.S. Pat. No. 3,308,069), Zeolite ZK-20 (U.S.Pat. No. 3,445,727), Zeolite ZSM-3 (U.S. Pat. No. 3,415,736), faujasite,LZ-10 (U.K. Patent 2,014,970, Jun. 9, 1982), ZSM-5-type zeolites, e.g.,ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48, crystallinesilicates such as silicalite (U.S. Pat. No. 4,061,724), erionite,mordenite, offretite, chabazite, FU-1-type zeolite, NU-type zeolites,LZ-210-type zeolite and mixtures thereof. Traditional cracking catalystscontaining amounts of Na₂ O less than about one percent by weight aregenerally preferred. The relative amounts of the SSZ-25 component andtraditional cracking component, if any, will depend at least in part, onthe selected hydrocarbon feedstock and on the desired productdistribution to be obtained therefrom, but in all instances an effectiveamount of SSZ-25 is employed. When a traditional cracking catalyst (TC)component is employed, the relative weight ratio of the TC to the SSZ-25is generally between about 1:10 and about 500:1, desirably between about1:10 and about 200:1, preferably between about 1:2 and about 50:1, andmost preferably is between about 1:1 and about 20:1.

The cracking catalysts are typically employed with an inorganic oxidematrix component which may be any of the inorganic oxide matrixcomponents which have been employed heretofore in the formulation of FCCcatalysts including: amorphous catalytic inorganic oxides, e.g.,catalytically active silica-aluminas, clays, silicas, aluminas,silica-aluminas, silica-zirconias, silica-magnesias, alumina-borias,alumina-titanias and the like and mixtures thereof.

The traditional cracking component and SSZ-25 may be mixed separatelywith the matrix component and then mixed or the TC component and SSZ-25may be mixed and then formed with the matrix component.

The mixture of a traditional cracking catalyst and SSZ-25 may be carriedout in any manner which results in the coincident presence of such incontact with the crude oil feedstock under catalytic crackingconditions. For example, a catalyst may be employed containing thetraditional cracking catalyst and a SSZ-25 in single catalyst particlesor SSZ-25 with or without a matrix component may be added as a discretecomponent to a traditional cracking catalyst.

SSZ-25 is especially useful as a catalyst in a process for isomerizingone or more xylene isomers in a C₈ aromatic feed to obtain ortho-, meta-and para-xylene in a ratio approaching the equilibrium value. Inparticular, xylene isomerization is used in conjunction with aseparation process to manufacture para-xylene. For example, a portion ofthe para-xylene in a mixed C₈ aromatics stream may be recovered bycrystallization and centrifugation. The mother liquor from thecrystallizer is then reacted under xylene isomerization conditions torestore ortho-, meta-, and para-xylenes to a near equilibrium ratio. Atthe same time, part of the ethylbenzene in the mother liquor isconverted to xylenes or to products which are easily separated bydistillation. The isomerate is blended with fresh feed and the combinedstream is distilled to remove heavy and light by-products. The resultantC₈ aromatics stream is then sent to the crystallizer to repeat thecycle.

Xylene isomerization catalysts are judged on their ability to produce anear equilibrium mixture of xylenes and convert ethylbenzene with verylittle net loss of xylenes. The SSZ-25 type zeolites are especiallyeffective in this regard. Accordingly, an additional aspect of thepresent invention is to provide a hydrocarbon conversion process whichcomprises contacting a C₈ aromatic stream of xylene ethylbenzene ormixture thereof, as well as a mixture of ethylbenzenes and otheralkylbenzenes under isomerization conditions with a catalyst comprisingSSZ-25.

The SSZ-25 may conveniently be used as an aggregate in the form ofpellets or extrudates. An inorganic oxide binder such as gamma aluminaor silica may be employed to provide attrition resistance.

In the vapor phase, suitable isomerization conditions include atemperature in the range 500°-1100° F., preferably 600°-1050° F., apressure in the range 0.5-50 atm abs, preferably 1-5 atm abs, and aweight hourly space velocity (WHSV) of 0.1 to 100, preferably 0.5 to 50.Optionally, isomerization in the vapor phase is conducted in thepresence of 3.0 to 30.0 moles of hydrogen per mole of alkylbenzene. Ifhydrogen is used, the catalyst should comprise 0.1 to 2.0 wt. % of ahydrogenation/dehydrogenation component selected from Group VIII of thePeriodic Table, especially platinum or nickel. By Group VIII metalcomponent is meant the metals and their compounds such as oxides andsulfides.

In the liquid phase, suitable isomerization conditions include atemperature in the range 100°-700° F., a pressure in the range 1-200 atmabs, and a WHSV in the range 0.5-50.

Optionally, the isomerization feed may contain 10 to 90 wt. % of adiluent such as toluene, trimethylbenzenes, naphthenes or paraffins.

SSZ-25 can also be used to oligomerize straight and branched chainolefins having from about 2 to 21 and preferably 2-5 carbon atoms. Theoligomers which are the products of the process are medium to heavyolefins which are useful for both fuels, i.e., gasoline or a gasolineblending stock and chemicals.

The oligomerization process comprises contacting the olefin feedstock inthe gaseous state phase with SSZ-25 at a temperature of from about 450°F. to about 1200° F., a WHSV of from about 0.2 to about 50 and ahydrocarbon partial pressure of from about 0.1 to about 50 atmospheres.

Also, temperatures below about 450° F. may be used to oligomerize thefeedstock, when the feedstock is in the liquid phase when contacting thezeolite catalyst. Thus, when the olefin feedstock contacts the zeolitecatalyst in the liquid phase, temperatures of from about 50° F. to about450° F., and preferably from 80° to 400° F. may be used and a WHSV offrom about 0.05 to 20 and preferably 0.1 to 10. It will be appreciatedthat the pressures employed must be sufficient to maintain the system inthe liquid phase. As is known in the art, the pressure will be afunction of the number of carbon atoms of the feed olefin and thetemperature. Suitable pressures include from about 0 psig to about 3000psig.

The zeolite can have the original cations associated therewith replacedby a wide variety of other cations according to techniques well known inthe art. Typical cations would include hydrogen, ammonium and metalcations including mixtures of the same. Of the replacing metalliccations, particular preference is given to cations of metals such asrare earth metals, manganese, calcium, as well as metals of Group II ofthe Periodic Table, e.g., zinc, and Group VIII of the Periodic Table,e.g., nickel. One of the prime requisites is that the zeolite have afairly low aromatization activity, i.e., in which the amount ofaromatics produced is not more than about 20% by weight. This isaccomplished by using a zeolite with controlled acid activity [alphavalue] of from about 0.1 to about 120, preferably from about 0.1 toabout 100, as measured by its ability to crack n-hexane.

Alpha value are defined by a standard test known in the art, e.g., asshown in U.S. Pat. No. 3,960,978 which is incorporated totally herein byreference. If required, such zeolites may be obtained by steaming, byuse in a conversion process or by any other method which may occur toone skilled in this art.

SSZ-25 can be used to convert light gas C₂ -C₆ paraffins and/or olefinsto higher molecular weight hydrocarbons including aromatic compounds.Operating temperatures of 100° C.-700° C., operating pressures of 0 to1000 psig and space velocities of 0.5-40 hr⁻¹ WHSV (weight hourly spacevelocity) can be used to convert the C₂ -C₆ paraffin and/or olefins toaromatic compounds. Preferably, the zeolite will contain a catalystmetal or metal oxide wherein said metal is selected from the groupconsisting of Group IB, IIB, VIII and IIIA of the Periodic Table, andmost preferably gallium and in the range of from about 0.05 to 5% byweight.

SSZ-25 can be used to condense lower aliphatic alcohols having 1 to 8carbon atoms to a gasoline boiling point hydrocarbon product comprisingmixed aliphatic and aromatic hydrocarbon. The condensation reactionproceeds at a temperature of about 500° F. to 1000° F., a pressure ofabout 0.5 to 1000 psig and a space velocity of about 0.5 to 50 WHSV. Theprocess disclosed in U.S. Pat. No. 3,984,107 more specifically describesthe process conditions used in this process, which patent isincorporated totally herein by reference.

The catalyst may be in the hydrogen form or may be base exchanged orimpregnated to contain ammonium or a metal cation complement, preferablyin the range of from about 0.05 to 5% by weight. The metal cations thatmay be present include any of the metals of the Groups I through VIII ofthe Periodic Table. However, in the case of Group IA metals, the cationcontent should in no case be so large as to effectively inactivate thecatalyst.

The conversion of hydrocarbonaceous feeds can take place in anyconvenient mode, for example, in fluidized bed, moving bed, or fixed bedreactors depending on the types of process desired. The formulation ofthe catalyst particles will vary depending on the conversion process andmethod of operation.

Other reactions which can be performed using the catalyst of thisinvention containing a metal, e.g., platinum, includehydrogenation-dehydrogenation reactions, denitrogenation anddesulfurization reactions.

SSZ-25 can be used in hydrocarbon conversion reactions with active orinactive supports, with organic or inorganic binders, and with andwithout added metals. These reactions are well known to the art, as arethe reaction conditions.

SSZ-25 can also be used as an adsorbent, as a filler in paper, paint,and toothpastes, and as a water-softening agent in detergents.

The following Examples illustrate the preparation of SSZ-25.

EXAMPLES Example 1

Preparation of N,N,N-Trimethyl-1-adamantanammonium Hydroxide (TemplateA)

Ten (10) grams of 1-adamantanamine (Aldrich) was dissolved in a mixtureof 29 gms tributylamine and 60 mls dimethylformamide. The mixture waschilled in an ice bath.

28.4 Grams of methyl iodide were added dropwise to the chilled solutionwith continuous stirring. After several hours, crystals appear. Thereaction was continued overnight and allowed to come to roomtemperature. The crystals were filtered and washed with tetrahydrofuranand then diethyl ether before vacuum drying. Additional product wasobtained by adding enough diethyl ether to the reaction filtrate toproduce two phases and then with vigorous stirring acetone was addeduntil the solution just became one phase. Continued stirring producedcrystallization at which time the solution can be chilled to inducefurther crystallization. The product has a melting point near 300° C.(decomp.) and the elemental analyses and NMR are consistent with theknown structure. The vacuum-dried iodide salt was then ion-exchangedwith ion-exchange resin AG 1×8 (in molar excess) to the hydroxide form.The exchange was performed over a column or more preferably by overnightstirring of the resin beads and the iodide salt in an aqueous solutiondesigned to give about a 0.5 molar solution of the organic hydroxide.This produces Template A.

Example 2

Preparation of N,N,N-Trimethyl-2-adamantan-ammonium Hydroxide (TemplateB)

Five grams of 2-adamantanone (Aldrich Chemical Co.) was mixed with 2.63gms of formic acid (88%) and 4.5 gms of dimethyl formamide. The mixturewas then heated in a pressure vessel for 16 hours at 190° C. Care shouldbe taken to anticipate the increase in pressure the reaction experiencesdue to CO₂ evoluation. The reaction was conveniently carried out in aParr 4748 reactor with teflon liner. The workup consists of extractingN,N dimethyl-2-adamantamine from a basic (pH=12) aqueous solution withdiethyl ether. The various extracts were dried with Na₂ SO₄, the solventremoved and the product taken up in ethyl acetate. An excess of methyliodide was added to a cooled solution which was then stirred at roomtemperature for several days. The crystals were collected and washedwith diethyl ether to give N,N,N trimethyl-2-adamantammonium iodide. Theproduct is checked by microanalysis for C, H, and N. The conversion tothe hydroxide form was carried out analogously to Template A above.

Example 3

4.5 Grams of a 0.67 M solution of Template B in its hydroxide form weremixed with 6 ml H₂ O and 0.103 gms of KOH (solid). After dissolution,2.36 gms of Ludox AS-30 colloidal silica (30% SiO₂) were added withstirring using a magnetic stir bar. Finally, 0.78 gms of Nalco 1SJ612alumina on silica (30% solids, 4% Al₂ O₃ overall) was added. Thereactants were loaded into a Parr 4745 reactor, sealed and loaded onto arotating spit in a Blue M oven. The reactor was rotated at 30 RPM whilebeing heated at 175° C. for 10 days. The product after filtration,washing with distilled water, drying in air and then at 100° C. was thecrystalline material designated SSZ-25. The X-ray diffraction pattern ofthe as-made material is tabulated in Table 4 below.

                  TABLE 4                                                         ______________________________________                                        2 θ       d/n     I/I.sub.o                                             ______________________________________                                        3.05            29.0    20                                                    6.42            13.77   100                                                   7.18            12.31   100                                                   7.88            11.22   47                                                    9.62            9.19    53                                                    12.85           6.89    13                                                    14.37           6.16    10                                                    14.73           6.01    23                                                    15.75           5.63    27                                                    16.13           5.49    13                                                    19.37           4.58    47                                                    20.09           4.42    23                                                    20.78           4.27    10                                                    21.65           4.105   50                                                    22.57           3.939   50                                                    23.05           3.858   30                                                    23.70           3.754   17                                                    25.00           3.565   20                                                    26.03           3.423   73                                                    26.85           3.320   33                                                    27.28           3.269   17                                                    28.91           3.088   13                                                    ______________________________________                                    

Example 4

6.02 Grams of a 0.71M solution of Template A were mixed with 0.14 gmsKOH(s), 0.088 gms of Reheis F-2000 hydrated alumina, and 8 ml H₂ O.After thorough mixing, 4.0 gms of Ludox AS-30 was blended in as silicasource. The reaction mixture was heated in the teflon cup of a Parr 4745reactor at 175° C. at 435 RPM for 7 days. Workup as in Example 3produced crystalline SSZ-25.

Example 5

In this example, the same reactants were used as in Example 4 but theinitial SiO₂ /Al₂ O₃ ratio was increased to 75. 0.051 of Reheis F-2000hydrated alumina was used and dissolved in the same quantity KOH, 6.4gms of the same Template A solution and 6.8 ml H₂ O. The same quantityof Ludox was used and the reaction was again run at 175° C. but at 30RPM. At 7 days of reaction, the product was largely amorphous but by 10days of reaction the product was crystalline SSZ-25. The SiO₂ /Al₂ O₃value of the zeolite is 75.

Example 6

3.00 Grams of a 1.04M solution of Template A was mixed with 9 ml of H₂O, 0.195 gms of KOH(s), 0.083 gms of Reheis F-2000 hydrated alumina, andfinally 0.90 gms of Cabosil M5. The mixture was heated at 175° C. for 7days without agitation. The crystalline product was SSZ-25 and has aSiO₂ /Al₂ O₃ ratio of 30.

Example 7

A reaction like Example 4 was set up again. This time a half-inchdiameter teflon ball was added to the reactor to aid in mixing duringthe tumbling of the reactor. The crystalline product after 7 days ofreaction and the usual workup was SSZ-25.

Example 8

The crystalline products of Examples 3-7 were subjected to calcinationas follows. The samples were heated in a muffler furnace from roomtemperature up to 540° C. at a steadily increasing rate over a 7-hourperiod. The samples were maintained at 540° C. for four more hours andthen taken up to 600° C. for an additional four hours. A 50/50 mixtureof air and nitrogen was passed over the zeolites at a rate of 20standard cubic feet per minute during heating.

Representative X-ray diffraction data for the calcined products ofExample 3 appears in Table 5.

                  TABLE 5                                                         ______________________________________                                        2 θ       d/n     I/I.sub.o                                             ______________________________________                                        3.35            26.4    18                                                    7.18            12.31   100                                                   8.00            11.05   62                                                    10.04           8.80    68                                                    12.90           6.86    12                                                    14.33           6.18    44                                                    14.80           5.99    12                                                    16.01           5.53    18                                                    20.31           4.37    18                                                    21.70           4.10    44                                                    22.73           3.91    41                                                    23.80           3.74    24                                                    25.02           3.559   15                                                    26.06           3.420   68                                                    27.02           3.300   15                                                    27.89           3.999   18                                                    28.71           3.109   12                                                    ______________________________________                                    

The SSZ-25 product of Example 4 was also calcined in a muffler furnaceat 463° C. for a period of 2 hours and the representative X-raydiffraction data for the calcined product appears in Table 6 below.

                  TABLE 6                                                         ______________________________________                                        2 θ       d/n     I/I.sub.o                                             ______________________________________                                        3.5             25.2    16                                                    7.20            12.28   110                                                   8.07            10.96   47                                                    9.68            9.14    74                                                    10.08           8.77    58                                                    13.05           6.78    15                                                    14.37           6.16    36                                                    14.82           5.98    11                                                    16.10           5.50    16                                                    18.03           4.92     8                                                    20.30           4.37    12                                                    20.95           4.24    18                                                    21.66           4.10    11                                                    21.97           4.05    18                                                    22.80           3.900   34                                                    23.80           3.739   18                                                    25.03           3.558   14                                                    25.32           3.517   15                                                    26.10           3.414   61                                                    27.05           3.296   15                                                    27.95           3.192   14                                                    28.71           3.109   11                                                    ______________________________________                                    

Considerable changes in peak position and intensity can be observed incomparing the data for SSZ-25 before and after calcination.

Example 9

Ion-exchange of the calcined SSZ-25 materials from Example 18 wascarried out using NH₄ NO₃ to convert the zeolites from their K form toNH₄ and then eventually H form. Typically the same mass of NH₄ NO₃ aszeolite was slurried into H₂ O at ratio of 50/1 H₂ O to zeolite. Theexchange solution was heated at 100° C. for two hours and then filtered.This process was reported four times. Finally, after the last exchangethe zeolite was washed several times with H₂ O and dried. A repeatcalcination as in Example 8 was carried out but without the finaltreatment at 600° C. This produces the H form of SSZ-25 zeolite.

Example 10

The product of Example 6, after sequential treatment as in Examples 8and then 9, was subjected to a surface area and pore size distributionanalysis using N₂ as adsorbate and via the BET method. The surface areaof the zeolitic material was 520 m² /gm and the micropore volume was0.18 cc/gm.

Example 11 Constraint Index Determination

0.25 Grams of the hydrogen form of the zeolite of Example 3 (aftertreatment according to Examples 8 and 9, was packed into a 3/8"stainless steel tube with alundum on both sides of the zeolite bed. ALindberg furnace was used to heat the reactor tube. Helium wasintroduced into the reactor tube at 10 cc/min. and atmospheric pressure.The reactor was taken to 250° F. for 40 min. and then raised to 600° F.Once temperature equilibration was achieved, a 50/50, w/w feed ofn-hexane and 3-methylpentane was introduced into the reactor at a rateof 0.62 cc/hr. Feed delivery was made via syringe pump. Direct samplingonto a gas chromatograph begun after 10 minutes of feed introduction.The constraint index value was calculated from gas chromatographic datausing methods known in the art.

    ______________________________________                                        Example No.                                                                            C.I.     Conversion at 10 min.                                                                        Temp. °F.                             ______________________________________                                        3        0.3      65%            600                                          ______________________________________                                    

Example 12

The following example illustrates the use of SSZ-25 as a reformingcatalyst. The hydrogen form of SSZ-25 was prepared as in Ex. 9. Thecatalyst was then back-exchanged at pH=10 with KOH at 80° C. Aftercalcination at 1000° F., the catalyst showed no cracking activity at800° F. The catalyst was impregnated with an aqueous solution ofplatinum tetramine dinitrate to give a platinum loading of 0.8%. Aftercalcination, the screening test was run on a light paraffinic C₅ -C₇straight run feed as follows:

LHSV=6

H₂ /HC=6

Psig=100

Temp.=860

After several hours on stream, the catalyst showed about 40% conversionof the C₆ and C₇ paraffins with a 35% selectivity to aromaticsconsisting chiefly of benzene, toluene and xylenes.

Example 13

The acid form of SSZ-25 was prepared as in Ex. 9 and tested for theconversion of methanol to liquid products, 0.5 gm of catalyst was loadedinto a 3/8" stainless steel reactor tube which was heated in a Lindbergfurnace to 1000° F. The temperature was reduced to 700° F. in a streamof helium at 20 cc/min. Methanol was introduced into the reactor at arate of 1.25 cc/hr. The conversion at 10 minutes was close to 100% anddropped only slightly over several hours, The product distribution isgiven in Table 7 below.

                  TABLE 7                                                         ______________________________________                                        Conversion of Methanol over SSZ-25 zeolite (at 85 min.)                       Product          wt. %                                                        ______________________________________                                        Methane          0.4                                                          Ethylene         1.1                                                          Ethane           0.0                                                          Propylene        3.2                                                          Propane          2.2                                                          Methanol         0.0                                                          Dimethyl Ether   0.0                                                          C.sub.4          10.3                                                         C.sub.5          6.8                                                          C.sub.6 (non-aromatic)                                                                         7.2                                                          Benzene          0.0                                                          Toluene          5.8                                                          p, m Xylene      13.1                                                         o, Xylene        4.7                                                          C.sub.6 +        38.5                                                         ______________________________________                                    

As can be seen in the table, the SSZ-25 makes very little light gas andproduces considerable liquid product under these conditions.

Example 14

When the hydrogen form of SSZ-25 is ion-exchanged with Ga₂ (SO₄)₃ atreflux for several hours and then calcined, a catalyst is produced whichis capable of aromatization under cracking conditions. When theconstraint index test was run as in Example 11 but at 800° F., theconversion was greater than 70% with greater than 50% of the product asaromatics.

Example 15

The same catalyst as in Example 14 is tested for aromatization ofn-butane at 940° F. The feed is 2% n-butane in helium run at atmosphericpressure. As the space rate is adjusted, for conversions of about 45%and greater, the yield of aromatics is 45-50% demonstrating the abilityof the gallium exchanged SSZ-25 to convert light gases to aromatics.

Example 16

The hydrogen form of the SSZ-25 zeolite may also be advantageously usedin the isomerization of xylenes and conversion of ethylbenzene. Thehydrogen form of the SSZ-25 zeolite was tested as catalyst for xyleneisomerization. A portion of the HSSZ-25 powder from Example 9 waspelleted, crushed and sieved to obtain 20-40 mesh granules, which werethen calcined for four hours at 1000° F. One gram of the calcinedmaterial was charged to a 3/16-inch I.D. tubular microreactor heated byan electric furnace. The catalyst bed was heated to 750° F. in flowinghelium. The helium was then replaced with a mixed xylene feed. The feedcomposition and reactor effluent were analyzed by gas chromatography.The test results are shown in Table 8. The HSSZ-25 catalyst produced anear equilibrium mixture of xylene isomers with excellent ethylbenzeneconversion and very little xylene loss.

                  TABLE 8                                                         ______________________________________                                        Xylene Isomerization Over HSSZ-25                                             ______________________________________                                        Hours on Stream        8-23                                                   Temperature, °F.                                                                              750                                                    WHSV                    5                                                     Pressure, psig          23                                                    ______________________________________                                        Composition, wt. %  Feed   Percent                                            ______________________________________                                        non-aromatics       0.44   1.05                                               benzene             0.00   1.99                                               toluene             1.34   3.69                                               ethylbenzene        9.76   6.37                                               p-xylene            9.61   19.37                                              m-xylene            53.99  43.06                                              o-xylene            23.10  20.00                                              heavy aromatics     1.77   4.46                                               Percent EB conversion      34.7                                               Percent xylene loss        4.3                                                p-xyl % approach to equil. 99.6                                               ______________________________________                                    

Example 17

The hydrogen form of SSZ-25 can be used in catalytic cracking. For suchpurposes, the catalyst prepared as in Ex. 9 was tested in amicro-activity test (MAT) using the procedure developed by ASTMCommittee D-32. The test was run at 925° F. on fresh catalyst at acat/oil ratio of 3 (based upon catalyst calcined to 1100° F.) and a WHSVof 15-16. Table 9 shows inspections on the feed and the resultingproducts. The catalyst was run at 20 wt. % in a kaolin matrix.

                  TABLE 9                                                         ______________________________________                                        MAT Test for SSZ-25 Zeolite                                                   ______________________________________                                        FEED                                                                          API                 29.09                                                     Aniline pt, °F.                                                                            219.1                                                     Ramsbottom Carbon, wt. %                                                                          0.3                                                       N (T), ppm          270                                                       N (B), ppm          159                                                       S (T), wt. %        0.54                                                      TEST DATA                                                                     Conversion, wt. %   55.2                                                      Coke, wt. %         4.7                                                       C.sub.5 -430° F.                                                                           22.0                                                      430-650° F.  19.0                                                      650+                26.0                                                      C.sub.3 -           13.6                                                      C.sub.4 -           28.5                                                      C.sub.4 olefin/C.sub.4 total                                                                      0.46                                                      ______________________________________                                    

Example 18

The hydrogen form of SSZ-25 as prepared in Ex. 9 can also be used as adewaxing catalyst selectively removing n-paraffins from waxy feeds. Thedewaxing catalyst is prepared as an extrudate with platinum on thezeolite. The zeolite comprises only 5% of the extrudate, the remainderbeing Catapal alumina. The platinum loading on the zeolite was 1%. 2.5gms of hydrogen SSZ-25 are added to a blend of 33.93 gms of Catapalalumina (70% Al₂ O₃) and 34.62 gms of Kaiser alumina (68.6% Al₂ O₃). 20cc of 10% HNO₃ are added slowly with mixing and then another 30 cc H₂ Oare added to give a dough-like consistency. The bound zeolite is driedovernight under partial vacuum at 120° C. Calcination is carried out at450° F. for 1 hour, followed by 1000° F. for an hour.

30 ml of methanol are added to 12 gms of the calcined extrudate. 0.26gms of platinum tetramine dinitrate in 24 cc H₂ O is added to themethanol/catalyst slurry. The mixture is tumbled while under vacuum andat 110° C. to slowly remove the co-solvent system over a 1.25 hr.period. After drying overnight at 120° C. and partial vacuum, thecatalyst is calcined at 450° F. for 2 hrs. and 900° F. for 1 hr.

6.2 cc of catalyst (24-48 mesh) were loaded into a 3/8" reactor tubewhich was placed in a furnace. The catalyst was dried at 400° F. undernitrogen (1000 psi) for an hour. The temperature was reduced to 300° F.,the gas inlet was switched to hydrogen (2150 psi) and the catalyst bedwas brought to 650° F. in 25 deg./half-hour increments.

Table 10 shows the characteristics of the waxy, hydrocracked AlaskanNorth Slope Medium Neutral VGO feed. Also shown is data for pour pointreduction as a function of temperature using the catalyst preparedabove.

                  TABLE 10                                                        ______________________________________                                        Use of SSZ-25 in Pour Point Reduction of Waxy Lube Stock                      ______________________________________                                        FEED                                                                          API                34.0                                                       Aniline pt, °F.                                                                          244.0                                                       Sulfur, ug/ul      0.34                                                       Nitrogen, ug/ul    0.11                                                       Pour Point        100° F.                                              Paraffin content   25% (by mass spec.)                                        Naphthenes         62%                                                        Aromatics          13%                                                        ______________________________________                                        PRODUCT                                                                       Run Temp         600         660(*)                                           Lube Yield        72%         69%                                             Pour Point        20° F.                                                                             10° F.                                   Cloud Point       32° F.                                                                             40° F.                                   V.I. (corrected) 110         108                                              ______________________________________                                         *feed spiked with quinoline to give 3 ppm NH.sub.3 level in the H.sub.2       once through gas.                                                        

Example 19

The hydrogen form of the SSZ-25 zeolite can be used in hydrocrackingconversions of hydrocarbon feeds. The data shown in Table 11 is for theconversion of a feed made up of representative model compounds. The dataillustrates the high activity and shape-selectivity for SSZ-25 zeolitein hydroprocessing. The catalyst is active by itself or when a noblemetal is incorporated. One gram (dry basis) of catalyst was loaded intoa 1/4" reactor tube packed with alundum on either side of the bed. Thecatalyst was dried at 500° F. for 30 min. with 1200 psi H₂. The hydrogenflow rate is 55 cc/min. at atmospheric pressure and room temperature.The feed rate was 50 microliters/min. and the catalyst was equilibratedfor 2 hours at temperature before G.C. analysis.

                  TABLE 11                                                        ______________________________________                                        Hydroprocessing of a Model Feed with SSZ-25 Zeolite                                          FEED                SSZ-25                                     CATALYST       ALONE      SSZ-25   (0.5% Pd)                                  ______________________________________                                        TEMP.          --          700° F.                                                                         500° F.                            LHSV                                                                          H.sub.2 PRESSURE          1200     1200                                       CONVERSION                 49%      46%                                       PRODUCT/FEED wt. %                                                            C.sub.1 -C.sub.6                                                                             0.0         44.8     13%                                       2,2-dimethylbutane                                                                             0.99       0.90     0.95                                     Marker                                                                        Cyclohexane     30.8       0.43     30.2                                      Isooctane(2,2,4)                                                                               4.4        4.0      4.6                                      Methylcyclohexane                                                                              0.0        0.0     23.9                                      Toluene         30.8       21.7      0.0                                      3,4,Diethyl C.sub.6                                                                            5.5        5.3      4.6                                      4-Propyl heptane                                                                               5.5        9.5      4.2                                      n-Decane         5.6        0.75     1.3                                      t-Decalin        6.2        6.7      7.1                                      c-Decalin        4.7        1.2      0.6                                      n-Dodecane       5.6        0.0      0.6                                      ______________________________________                                    

As can be seen above, the catalyst has surprising selectivity forn-paraffins and a selectivity for cis decalin over the trans isomer. Thereactivity is also somewhat pressure dependent.

What is claimed is:
 1. A dewaxing process comprising contacting thehydrocarbon feedstock under dewaxing conditions with a zeolite having amole ratio of an oxide selected from silicon oxide, germanium oxide andmixtures thereof to an oxide selected from aluminum oxide, galliumoxide, iron oxide, boron oxide and mixtures thereof greater than about20:1 and having the X-ray diffraction lines of Table 2.